该问题通常是由于 VPC 配置不正确或 Lambda 函数没有与正确的 VPC 子网和安全组关联所致。解决方法是在 VPC 中创建一个私有子网，并将 Lambda 函数与该私有子网和安全组关联起来。下面是一个示例 CloudFormation 模板，用于创建一个带有 Lambda 函数的 VPC：

{
  "Resources": {
    "VPC": {
      "Type": "AWS::EC2::VPC",
      "Properties": {
        "CidrBlock": "10.0.0.0/16"
      }
    },
    "Subnet": {
      "Type": "AWS::EC2::Subnet",
      "Properties": {
        "VpcId": { "Ref": "VPC" },
        "CidrBlock": "10.0.1.0/24",
        "AvailabilityZone": "us-east-1a"
      }
    },
    "SecurityGroup": {
      "Type": "AWS::EC2::SecurityGroup",
      "Properties": {
        "VpcId": { "Ref": "VPC" },
        "GroupDescription": "Allow SSH and HTTP traffic",
        "SecurityGroupIngress": [
          {
            "IpProtocol": "tcp",
            "FromPort": "22",
            "ToPort": "22",
            "CidrIp": "0.0.0.0/0"
          },
          {
            "IpProtocol": "tcp",
            "FromPort": "80",
            "ToPort": "80",
            "CidrIp": "0.0.0.0/0"
          }
        ]
      }
    },
    "LambdaFunction": {
      "Type": "AWS::Lambda::Function",
      "Properties": {
        "Code": {
          "S3Bucket": { "Ref": "LambdaBucket" },
          "S3Key": { "Fn::Join": [ "/", [ { "Ref": "LambdaVersion" }, "lambda.zip" ] ] }
        },
        "FunctionName": "MyFunction",
        "Handler": "index.handler",
        "Role": { "Fn::GetAtt": [ "LambdaExecutionRole", "Arn" ] },
        "Runtime": "nodejs12.x",
        "Timeout": 30,
        "VpcConfig": {
          "SecurityGroupIds": [ { "Fn::GetAtt": [ "SecurityGroup", "GroupId" ] } ],
          "SubnetIds": [ { "Ref": "Subnet" } ]
        }
      }
    },
    "LambdaExecutionRole": {
      "Type": "AWS::IAM::Role",
      "Properties": {
        "AssumeRolePolicyDocument": {
          "Version": "2012-10-17",
          "Statement": [
            {
              "Sid": "",
              "Effect": "Allow",
              "Principal": {
                "Service": "lambda.amazonaws.com"
              },
              "Action": "sts:AssumeRole"
            }
          ]
        },
        "Policies": [
          {
            "PolicyName": "lambda-policy",
            "PolicyDocument": {
              "Version": "2012-10-17",
              "Statement": [
                {
                  "Sid": "",
                  "Effect": "Allow",
                  "Action": [
                    "logs:CreateLogGroup",
                    "logs:CreateLogStream",
                    "logs:PutLogEvents"
                  ],
                  "Resource": "arn:aws:logs:*:*:*"
                }
              ]
            }
          }
        ]
      }
    }
  }
}